Darwinopterus modularis is a very pretty fossil of a Jurassic pterosaur, which also reveals some interesting modes of evolution; modes that I daresay are indicative of significant processes in development, although this work is not a developmental study (I wish…having some pterosaur embryos would be exciting). Here it is, one gorgeous animal.

One important general fact you need to understand to grasp the significance of this specimen: Mesozoic flying reptiles are not all alike! There are two broad groups that can be distinguished by some consistent morphological characters.

The pterosaurs are the older of the two groups, appearing in the late Triassic. They tend to have relatively short skulls with several distinct openings, long cervical (neck) ribs, a short metacarpus (like the palm or sole of the foot), a long tail (with some exceptions), and an expanded flight membrane suspended between the hind limbs, called the cruropatagium. They tend to be small to medium-sized.

The pterodactyls are a more derived group that appear in the late Jurassic. Their skulls are long and low, and have a single large opening in front of the eyes, instead of two. Those neck ribs are gone or reduced, they have a long metacarpus and short tails, and they’ve greatly reduced the cruropatagium. Some of the pterodactyls grew to a huge size.

Here’s a snapshot of their distribution in time and phylogenetic relationships. The pterosaurs are in red, and the pterodactyls are in blue.

Darwinopterus is in there, too—it’s the small purple box numbered “7”. You can see from this diagram that it is a pterosaur in a very interesting position, just off the branch that gave rise to the pterodactyls. How it got there is interesting, too: it’s basically a pterosaur body with the head of a pterodactyl. Literally. The authors of this work carried out multiple phylogenetic analyses, and if they left the head out of the data, the computer would spit out the conclusion that this was a pterosaur; if they left the body out and just analyzed the skull, the computer would declare it a pterodactyl.

What does this tell us about evolution in general? That it can be modular. The transitional form between two species isn’t necessarily a simple intermediate between the two in all characters, but may be a mosaic: the anatomy may be a mix of pieces that resemble one species more than the other. In this case, what happened in the evolution of the pterodactyls was that first a pterodactyl-like skull evolved in a pterosaur lineage, and that was successful; later, the proto-pterodactyls added the post-cranial specializations. Not everything happened all at once, but stepwise.

This should be a familiar concept. In pterodactyls, skulls evolved a specialized morphology first, and the body was shaped by evolutionary processes later. We can see a similar principle in operation in the hominid lineage, too, but switched around. We evolved bipedalism first, in species like Ardipithecus and Australopithecus, and the specializations of our skull (to contain that big brain of which we are so proud) came along later.

As I mentioned at the beginning, this is an example of development and evolution in congruence. We do find modularity in developmental process — we have genetic circuits that are expressed in tissue- and region-specific ways in development. We can talk about patterns of gene expression that follow independent programs to build regions of the body, under the control of regional patterning genes like the Hox complex. In that sense, what we see in Darwinopterus is completely unsurprising.

What is interesting, though, is that these modules, which we’re used to seeing within the finer-grained process of development, also retain enough coherence and autonomy to be visible at the level of macroevolutionary change. It caters to my biases that we shouldn’t just pretend that all the details of development are plastic enough to be averaged out, or that the underlying ontogenetic processes will be overwhelmed by the exigencies of environmental factors, like selection. Development matters — it shapes the direction evolution can take.

Don’t be foolish, Jack. That’s no mix-up. That there is clearly a panda, its skeleton bent and distorted via the intricate processes of of Flood Geology (which I and every other person on earth am at a loss to describe in any meaningful detail, so instead I’ll just link to a picture of what we think the ark looked like.)

I see a a crack that runs across where the head attaches to the spine. Would it not be more parsimonious to say that they have mixed the head of one creature with the body of a different creature?

I think maybe the real question is how many fossils do not not have at least one broken bone? After all, some shift can occur during the fossilization process. Although, this is beautiful fossil in one layer with the bones in approximately right postions. So the parsimonious position would be that it is a real fossilized critter.

In other words, JackSpratt, just looking closely at the picture from this post should have made you realize that there were two different fossil specimens being shown. (a) and (b) are different than (f).

It really doesn’t matter to me much but these pictures do not support the idea that this is all one animal.
But there is no point in arguing it.
If anyone can point us to other pictures of other fossils that we can access for free please do so.
I have not seen any on google.

Ah, Mr. Sprat. Like we would take your word for anything without evidence. Which you fail to supply, and only give us your unsubstantiated opinion. Which is worthless. And given your lack of proper scientific training, probably less than worthless. So, time for you to quit arguing your inane point.

However you’re more than willing to give your unsubstantiated opinion.

You’ve been told where there’s another picture of D. modularis. But since that picture doesn’t support your pretense that the fossil is a fake, you’re ignoring it and demanding more information. We all know if you were given another picture and it didn’t support your pretense, you’d dismiss it as well. Sorry to disturb your creationist delusions but that’s a genuine fossil of a genuine pterosaur.

Now do you have anything substantial to offer or are you going to admit that your creationist bullshit is nothing but imaginary stupidity?

Mr. Sprat, until you can produce conclusive evidence for your inane claim, like being able to show by examining the fossil that the strata don’t line up, or the dating of the layers don’t match, all you have is hot air. So, go and look at the real fossil. If you have the proper credentials, you might even get to look at it up close. But, given your unscientific attitude to date, the chances of that happening are slim. You are wrong until you prove yourself right. And the scientists who wrote the paper have done their job at convincing fellow scientists they are right.

Mr. Spratt is putting the rest of you “skeptics” to shame here. He has sniffed out and zeroed directly in on the flaw, obvious in hindsight, that escaped the notice of all of the people who have directly examined the fossil itself. And he has done so using only internet photographs! (hey wait…Jack, are you Dave Peters? only Marjanovi? wll get that one)

Can’t you see he’s merely asking for more evidence before making up his mind on whether to believe in this possibly fakable and therefore clearly faked “animal”? Remember Piltdown! (not the commenter) Remember Archaeoraptor!! Remember uh Nebraska Man! HOAX!!! HOAX I TELL YOU!!!!

Oh, and Mr. Sprat, the fossil will remain as scientific fact until more science, in the form of a paper showing it is a hoax, is published in the peer reviewed literature. What you say at this blog is not science, and doesn’t effect science. If you choose not to accept this fossil as real, do yourself a favor and keep it to yourself while you collect the data to truly refute it.

Sorry about that. You were using the creationists’ arguments so well I assumed you were one. My apologies for not recognizing the difference between you and other people using the same arguments. BTW, it’s only a singlt apostrophe on ‘Tis.

What is this other picture you refer to? Please just point to it (a link or something) rather than referring to it. I do not know the picture you are referring to.

Jack Spratt,
What you are failing to take into account (one of many things, in fact) is that when assembling a fossil from fragments, the stone around the fossil also tells a story. If you look at sedimentary rock, it is clear that the strata are different from one layer to another. Size of particles, amount of cement (iron oxide in this case from the look), particle composition, compactness,…–they all have to match. In fact, you can even look at isotopic composition and it will vary throughout the different strata. This makes fakes easy to spot, and it assists experts in assembling the fossil.

“As I mentioned at the beginning, this is an example of development and evolution in congruence. We do find modularity in developmental process ? we have genetic circuits that are expressed in tissue- and region-specific ways in development. We can talk about patterns of gene expression that follow independent programs to build regions of the body, under the control of regional patterning genes like the Hox complex. In that sense, what we see in Darwinopterus is completely unsurprising.”

Okay. But how does that work in the case of “convergent evolution”. The animals are not related and yet still execute the same “independent programs”?

The animals are not related and yet still execute the same “independent programs”?

Evolution is sloppy. What works does get selected for, and selection is a very powerful force. And if selection works toward something as being the most selected, because it is the most efficient, shapes may overlap, be it flying (birds and bats) or swimming (sharks and dolphins). Scientists understand this concept. You are obviously not grounded in what evolution is or means. Try reading books by Dawkins (Greatest Show on Earth), Coyne (Why Evolution is True), or Shubin (Your Inner Fish) for basic evolution.

Jack, do you understand “form follows function”? do you understand that shared genomes can cause similar mutations even in divergent species, as long as the relevant chunk of the genome remains similar?

convergent evolution also isn’t usually about “the same”; it’s about “similar enough”.

All metazoans being ancestrally related does not explain instances of “convergent evolution”.

You did say they were not related, remember?

And no, it does not fully explain it, of itself. To do that, one also needs to take into account that form follows function, and similar ecospaces will require similar functions for success in any given ecological niche.

Okay. But how does that work in the case of “convergent evolution”. The animals are not related and yet still execute the same “independent programs”?

Same toolkit genes in all animals, plus similar ecological niches or conditions, selective pressures, a random mutation here and there, and you get development of analogous structures, what’s your problem ?
Birds and bats have wings, their common ancestor didn’t.
Similar things have happened all the time, look at marsupials and mammals.

“A random mutation here and there”.
It would be interesting to see somebody provide evidence that “random mutations” could happen often enough and quickly enough to explain any change that has ever occurred.
Can you provide any evidence that includes the rate of random mutations and the number of occurrences in an actual example from real life?

<sigh> The boring pseudonymous Woodmorappe, preaching as usual about things he doesn’t understand.

Summary

Recent claims about ?terrestrial? whales are examined and refuted. The trends cited in whale evolution are rather superficial in nature, and little different from those that become apparent by lining up wheeled vehicles within a cladogram. A close examination of whale evolution in general, and whale-ear evolution in particular, demonstrates that most anatomical traits do not change in a consistent whale-like direction. Recently discovered pakicetids consist of cetacean ?modules? within otherwise non-cetacean bodies. These extinct creatures are examples of chimeric creatures. The cetaceans, mesonychids, and artiodactyls share a number of anatomical traits in a pattern that is inconsistent with any type of evolutionary nested hierarchy, and this argues strongly for the special creation of all these creatures.

Those wheeled vehicles do in fact have a genealogical tree ? it’s just that it’s all in the heads of their designers, without actual procreation involved.

Of fucking course no traits change consistently in a whale-like direction. The tree of life isn’t a pole, it’s a tree. It branches. Natural selection doesn’t have any foresight, and mutation doesn’t have any sight at all… what Woodmorappe is looking at is diversification, and one branch of this bush has survived.

Woodmorappe believed the theory of evolution would predict consistent changes in a whale-like direction. This alone means he doesn’t understand what he’s talking about. It means I don’t even need to go on.

But I’ll do anyway. I haven’t even finished the above quote.

The modularity aspect is real, but Woodmorappe exaggerates it. For instance, while the skull of Darwinopterus/Wukongopterus is of a general pterodactyloid type, it isn’t identical to that of any particular pterodactyloid. Its tooth arrangement, for instance, is unique altogether in its details. (If you want the pdf of the paper, find me in Google Scholar and drop me an e-mail.)

The last sentence is Woodmorappe’s ignorance of convergence. Again, it’s not a pole, it’s a tree, and Woodmorappe hasn’t understood that.

Figure 1. The Chimera according to Greek mythology: part goat, part lion, and part snake.

That’s not a goat that figure is showing… it’s an ibex.

?But?, evolutionists commonly say, ?while individual traits, or small groups of traits can re-appear on an occasional and sporadic basis in different evolutionary lineages, it is inconceivable that a related series of numerous traits (i.e. a module) could re-appear in a concerted manner, at least to an extent sufficient to cause the development of incorrect phylogenies.?

What? Nobody is saying that (which is why the dishonest Woodmorappe doesn’t cite anyone for it). If they’re really related, to the extent that the presence of one of these traits requires the presence of all of them, then convergence in one automatically means convergence in all. And that happens.

And incorrect phylogenies absolutely do result when people don’t use enough information (which can be caused by simply not enough information being available). One case of this is what my PhD thesis is on.

Among marine invertebrates, the extinct cephalopods show such a bewildering assortment of chimeric conch morphologies that it is often difficult to distinguish presumed shared ancestry from convergence.

To be fair, that’s because nobody has ever tried. Nobody has conducted, to the best of my knowledge, a phylogenetic analysis of Cephalopoda with a reasonably large sample of species. There are just a few small proof-of-concept analyses that don’t help with this particular issue.

What?s more, these real-life chimeras also make it difficult to classify cephalopods according to higher taxonomic categories.

“More”?

Woodmorappe doesn’t seem to have noticed that reconstructing the evolutionary tree is what classification is nowadays. He’s repeating himself without noticing. He doesn’t understand what he’s talking about.

Let us now consider an example of chimeric creatures among land mammals. Hystricomorphy, a unique muskoskeletal pattern involving the jaw, enables the mouth to be opened in a large gape. Hystricomorphy is characteristic of the hystricomorph rodents, but has also now been found in the extinct saber-toothed Barbourofelis. Although it is believed that a highly-detailed phylogenetic analysis should spot the independent acquisition of the two complexes of traits, it is acknowledged that supposedly-unique character complexes could arise through convergence and ?fool? the evolutionist into believing that they had arisen from common ancestry.

That’s exactly why tree reconstruction can’t be done by using a single character or three.

It’s also why nobody does that anymore. Try 300 or 400 as a minimum.

That (half-convincing) evolutionary transitional forms number a mere handful only repeats what creationist scientists (for example, Duane T. Gish[…]) have been saying for decades, and squarely refutes the anti-creationists who adamantly insist that transitional forms are common.

<yawn> Not everyone is using the same definitions for “rare” and “transitional”. It’s a simple misunderstanding.

Calling Gish a scientist? That’s rich. Gish makes assumptions and states them; he never tests them.

Let us analyze what usually passes for ?transitions? in discussions surrounding the evolution of whales. To illustrate this, I have constructed a mock character-trait matrix (Table 1), and thence a cladogram (Figure 3) to show the gradual ?evolution? of a unicycle into an 18-wheeled truck.

Woodmorappe still hasn’t understood the difference between a tree and a pole, between a mother and an aunt. He then goes on to elaborate on this lack of understanding by again insisting there must be no convergence, as if there were only one environment which never changed erratically. It’s tiring.

The progressive reduction of hindlimbs is of dubious significance, if only because of the wide range of hindlimb sizes in the creatures involved. Moreover, modern whales sometimes sprout ?hindlimbs? of appreciable size (larger than those of ?ancestors?, and thereby contrary to the trend in hindlimb reduction). Finally, even greatly reduced hindlimbs lack any necessary evolutionary connotation.

Nonsense from front to back. Woodmorappe hasn’t even noticed that “hindlimb reduction” means “smaller hindlimbs compared to the forelimbs“; and it hasn’t crossed his mind that it’s advantageous to reduce and lose the unneeded hindlimbs ? they cause drag, and they need to be built and maintained with resources that could be invested in other things like faster growth or reproduction. There’s always natural selection for losing everything, except for those things on which there’s even stronger natural selection for keeping them.

Although different cladograms contradict each other, they are unanimous in grouping Pakicetus with Ambulocetus as sister groups.

The opposite is the case: they are unanimous in never finding these two as sister-groups. What’s going on is that Woodmorappe hasn’t understood what “sister-group” means and is too stupid to ask.

The sister-group of X is the branch that is only one node away from X. So, the sister-group of Ambulocetus is the large group composed of Remingtonocetidae, Rodhocetidae, Protocetidae, Dorudontidae, Basilosauridae, Mysticeti, and Odontoceti (according to Woodmorappe’s fig. 2). Both of these together ? Ambulocetus and the large group ? form the sister-group to Pakicetidae.

The National Geographic conspicuously fails to mention this sharp discontinuity in its slick portrayal of the ?Back to the Sea? parade[…] of creatures.

SHOCK HORROR!!!1! The once enormous gap between hippos and whales has shrunk to the much, much smaller gap between Pakicetidae and Ambulocetus! Someone call the waaaaaahmbulance already, and won’t somebody please think of the children!!1!!!

Man, is Woodmorappe making himself ridiculous.

Over here on Pharyngula, every new discovery of a halfway spectacular fossil that counts as transitional (in the sense the media or creationists would have it) gets commented by “oh well, two new gaps in the fossil record”. I just explained why.

scientific creationists

Scientific, or creationists?

Entirely omitted in the National Geographic article is the fact that, owing partly to preservation problems, there is a lack of intermediates between tails and flukes:

SHOCK HORROR!!!1! The once enormous gap between hippos and whales has shrunk to the much, much smaller gap between Rodhocetidae and Protocetidae! Someone call the waaaaaahmbulance already, and won’t somebody please think of the children!!1!!!

Woodmorappe making himself ridiculous again.

(And then again by failing to understand that the fluke is part of a tail.)

Isn’t it fascinating that we now have a stepwise pattern, where previously we could only say “all these traits must have evolved sometime in the ancestry of whales, probably not all at the same time, but we can’t tell in which order”? Now we can delimit the evolution of bigger, flatter feet to the origin of the Ambulocetus-Remingtonocetidae-Rodhocetidae-Protocetidae-Dorudontidae-Basilosauridae-Mysticeti-Odontoceti group after it and the ancestors of Pakicetidae had split, and the evolution of the fluke to the origin of the Protocetidae-Dorudontidae-Basilosauridae-Mysticeti-Odontoceti group after it and the ancestors of Rodhocetidae had split, showing us that the former happened earlier than the latter, which also happens to make sense from a biomechanical point of view.

When Archaeopteryx was discovered in eighteen sixty fucking one, creationists immediately demanded to see the intermediates between it and modern birds on the one side and between it and “reptiles” on the other. Immediately someone commented* that, if those additional intermediates were found, the creationists would demand to see the intermediates between the intermediates, and so on ad nauseam. Of course, that’s exactly what happened, and here we see it again with whales. It’s pathetic.

* The actual quote & citation from the early 1860s is in the book The Hot-Blooded Dinosaurs by Adrian J. Desmond, 1975. I don’t have it here, unfortunately.

We would never actually consider the bicycle as ancestral to the motor vehicles (Table 1, Figure 3) in spite of its ?structurally intermediate? character between the unicycle and the automobile. Why not free ourselves from the mental boxes of evolutionary thinking and give living things the same benefit?

Why then not view these extinct creatures as little more than ecological counterparts of extant seals, otters, etc., and forget all of the evolutionary tales that have them transformed to whales?

Because that’s what happened to happen later on, as far as the evidence says. It wouldn’t have been predictable when those animals actually lived, at least not in any detail.

To what extent are pakicetids intermediate in structure between the ?generic? artiodactyls on one hand and true cetaceans on the other?

Huh?

What sense does it make to cherry-pick them and leave the entire rest (see Woodmorappe’s fig. 2, and Indohyus) out?

Evolution is a process. You can’t see a process by looking at a single stage of it.

As if all this were not enough, the few pakicetid traits once believed unambiguously indicative of an aquatic or semi-aquatic transitional lifestyle, are no longer necessarily considered thus.[…] Consequently, the already borderline-deceptive practice[…] of sketching Pakicetus as a semiaquatic-adapted creature, in a very recent issue of National Geographic magazine,[…] is all the more inexcusable. And it is creationists who are supposed to be the purveyors of inaccurate and outdated information!

Woodmorappe should calm down and consider Indohyus and the extant Tragulidae (chevrotains).

none of the remaining three features show even a self-consistent, unidirectional change with time!

Again, this is expected. The Earth is not a laboratory where the environment changes steadily without the slightest back-and-forth wobbling for twenty million years, and a tree is not a pole.

The editors of National Geographic magazine would do well to communicate, very carefully to their lay audiences, the following sobering facts about the reconstruction of soft parts being unempirical (with very few exceptions), and in fact belief-driven:

The principle of parsimony is not a belief. But I didn’t actually expect Woodmorappe to know the uttermost basics of science theory. <sigh>

It cannot be stressed enough that, from an evolutionary point of view, organisms situated at the point of trait reversal are chimeras consisting of ?primitive? and ?derived? features, and they will not fit any nested hierarchy

if you are stupid enough to believe that convergence never happens.

Although 30% (183 of 603 data points) are missing, an astonishing 31% (21 out of the 67) traits are nonprogressive.

“Astonishing”? Woodmorappe’s knowledge of evolution is at the dinosaur-book-for-six-year-olds level.

It turns out that there is only one (one!) unambiguous bullar synapomorphy linking Pakicetus to the cetaceans, and simultaneously absent in all noncetacean animals.

Who cares about “all”? We expect most of these features to be present in at least some other mammals that hear underwater. What’s important is that they’re absent in the closest relatives of the whales.

from the ?evolutionary progression? point of view

Only creationists have such a point of view anymore. There is no progress. There’s only natural selection for better adaptation to the current environment; what the current environment is changes all the time.

There is a whole suite of features, found in archaeocete whales, which are believed to have become (conveniently) ?secondarily lost? (or ?reversed?) in the Odontocetes and Mysticetes.

Again, this had to be expected from the way evolution works outside simplistic laboratory settings and creationist minds.

Furthermore, rather than being the crown group of cetacean evolution (Figure 2), the extant mysticete and odontocete whales stand out as chimeras consisting of mostly derived but also many primitive features.

For crying out loud! The crown group of X is, by definition, the last common ancestor of all living members of X, plus all descendants of that ancestor! It doesn’t mean “pinnacle of creation” or any other such metaphysical mumbo-jumbo!

To pick one blatant example of a reversal, the crown-group whales have lost the contact between the sacral vertebrae and the (much reduced) pelvis. This is a reversal to a state last seen in their ancestors 300 million years earlier. It also makes sense, because a strong connection to useless reduced hindlimbs simply isn’t needed.

Believe it or not, the hoary and long-discredited[…] embryonic-recapitulation theory is dusted off and employed by some whale-evolution specialists[…] to infer the supposed fine stages of cetacean ear evolution. The fact that evolutionists feel the need to fall back on the recapitulation theory in order to infer alleged evolutionary changes is itself mute testimony to the fact that detailed structural intermediates illustrative of alleged cetacean aural evolution are lacking.

Woodmorappe seems to think it’s an all-or-nothing issue: either ontogeny recapitulates phylogeny in every single detail, or it has nothing at all to do with evolution whatsofuckingever.

He’s wrong.

Ontogeny evolves. That’s why we can’t simply watch it and pretend we’re watching a rerun of evolution (and Haeckel was wrong about this, though even he wasn’t that extreme actually); but it also means that shared derived characters in development can be used as data for reconstructing family trees, the same way data from adult morphology or from DNA can. Like the other two sources of data, development is subject to convergence, reversal, and so on, but, again like the other two, it’s not random noise either; it contains phylogenetic signal.

The pakicetids are an interesting set of chimeric creatures, consisting of an artiodactyl-like ankle and a somewhat true-cetacean-like inner ear residing in a body that is otherwise hardly distinguishable from that of a typical extinct land-dwelling artiodactyl!:

A typical extinct land-dwelling artiodactyl with a rather crocodile-like head…

For the rest of the body (other than the head), see Indohyus and the chevrotains. For the head, have a loot at the entelodonts and the mesonychians for comparison.

Ambulocetus is recognized as a whale because of characters of its teeth and skull that it shares with other whales

That’s a gross oversimplification (there are whale features all over the body). Woodmorappe pretends it’s not. Well, probably he doesn’t even know what an oversimplification it is.

does nothing significant to close the huge chasm between pakicetids and true cetaceans

Insert the “shock horror” paragraph again.

Figure 4. Mesonychians as the sister group of the Cetaceans. The chimeric mammalian orders, and failed nested hierarchy, are subject to either (or both) secondary-loss rationalizations (left), or convergent-evolution rationalizations (right).

Fascinating how Woodmorappe completely fails to mention the simplest explanation ? that mesonychians and whales are not sister-groups, but that mesonychians and artiodactyls are instead, while the whales are artiodactyls.

Further fascinating how he fails to cite the papers that have found just this simplest explanation in their analyses.

synapomorphy (shared form)

Shared derived character state.

One more case of Woodmorappe believing he knows what he’s talking about when he doesn’t. It’s about time I cite the Dunning-Kruger effect.

How much more parsimonious to recognize an Intelligent Designer who used the same anatomical modulus in otherwise-different mammalian orders?

More parsimonious? To conjure a being with magical powers out of thin air? When we don’t need it to explain anything? More parsimonious?

Alternatively, the cetacean-like teeth of mesonychians must be the product of convergent evolution (Figure 5, right). The latter rationalization, in fact, is the one that appears widely accepted by evolutionists.[…] Such thinking constitutes a revolution of sorts in mammalian paleontology. Prior to the recent turn of events, teeth had been used for construction of mammalian phylogenies, more or less uncritically, for over a century. All this time, dental features had been generally considered too detailed to be capable of being duplicated independently via convergent evolution.

Surprisingly, this part is actually correct (even though it’s a bit exaggerated*). Many of those tooth characters are correlated with each other, so counting them separately amounts to counting a single character several times. Development genetics (PZ’s field) has started to give us some insight into this.

* Most importantly, the “too detailed” part is a probability argument, not a claim of absolutes.

It invokes nonexistent fossils to resolve problems in known ones.

Wake me up when Woodmorappe shows me the skeletons of his ancestors unto the seven hundredth generation.

What do these people imagine the fossil record is like?

In answer to the questions posed by the title of this report, the answers are: 1). No, walking whales do not exist. Just because pakicetids have somewhat cetacean-like middle ears and cetartiodactyla-type double-pulleyed heel bones, this does not yet make them whales?unless of course one is willing to entertain the most ludicrously-strained definition of a whale.

It does indeed depend on the definition of “whale”.

If “whale” is defined as “everything more closely related to today’s whales than to the hippos”, then the pakicetids are whales. (“Closely related” is short for “sharing more recent common ancestors with”.) That’s the definition paleontologists are using these days.

Owing to widespread so-called evolutionary convergence, a nested hierarchy of living things exists only in part. The more detailed the anatomical analysis, the more the nested hierarchy breaks down.

Not to the point that we’d get phylogenetic grass in our analyses instead of a phylogenetic tree.

Whenever evolutionists make assertions about the limits of convergence

Such assertions were fashionable till the 1960s or so, when people had strange ideas about how evolution worked because they didn’t know what we know today about genetics, fossils, and so on. Today, nobody outside of Russia makes such assertions anymore; what we’re making are arguments from parsimony ? from science ? about which hypotheses we should prefer.

The apparent absence of extremely-chimeric creatures cannot, by any standard of reasoning, be accepted as evidence for evolution.

It would be interesting to see somebody provide evidence that “random mutations” could happen often enough and quickly enough to explain any change that has ever occurred.

I’ve seen the evolution of resistance to a virus in a petri dish full of Escherichia coli, overnight…

Define “often enough and quickly enough”.

Can you provide any evidence that includes the rate of random mutations and the number of occurrences in an actual example from real life?

The total number of mutations per generation is 100 to 200 in humans; Google will tell you how this was determined.

For the rate of mutations that affect the shape of the organism, you’ll have to turn to bacteria and viruses; such studies have been done, but aren’t easy, so there aren’t many of them. Still, Google should find some.

Especially read up on Lenski’s experiment; that one isn’t about shape, but about ecological niche, which is what shape mostly is about in animals.